Psalm 1: verse 1 - Christ the perfect man

leaf from Bentivoglio Bible, c1270

Today I want to take a look at the first verse of Psalm 1.

Today's post will be a bit longer than most - of the rest of the series on this psalm I'll be using the same methodology and abbreviations, but without the detailed explanations.  I'm also providing somewhat more detailed notes on this psalm than I plan to in future, in order to illustrate how to make use of the material I provide such as the assorted translations.

Saying and understanding the Latin

Pronouncing and singing the Latin

First of all I want to focus on the pronunciation of the Latin.

The sound file below provides a recording of verse 1 of the psalm said slowly with lots of repetitions of phrases so you can learn it; then sung on one note; then sing it using tone 8, which is used for most Mondays in the Office at Prime.

Note: my accent and singing is far from perfect, but I've included it as a learning tool on the basis that something is (probably) better than nothing, as I've had numerous requests from those still struggling with Latin pronunciation and who find the assorted podcasts I've previously pointed to a little too fast.  Hopefully over time those concerned will graduate to better models!

The recording uses the Vulgate translation from the Greek Septuagint (also included below for those to whom it may be of interest).  For this verse, it is identical to the Old Roman version of the psalter that pre-dated the Vulgate, and continued to be used in many places until around 1000 AD.

Versions of the Latin

There are two other versions of the Latin of the psalm you may encounter and are worth noting.

The first is the 1979 neo-Vulgate, used by many monasteries who have adopted the Ordinary Form of the Mass.

In this case it follows the important version, St Jerome's translation from the Hebrew (I'm afraid I haven't quite worked out how to get the Hebrew to copy in correctly or I would have added that too, for reference purposes, but you can look at it here if you are interested).

Personally I think the move away from 'cathedra pestilentiae' (seat of pestilence) to 'conventu derisorum' (gathering of scoffers) is unfortunate, as the word cathedra has a lot more resonances for Catholics, and the notion of a pestilential infection is rather more vivid to my mind.

Vulgate (V)	Beatus vir qui non abiit in consilio impiorum et in via peccatorum non stetit, et in cathedra pestilentiae non sedit.
Neo-Vulgate (NV)	Beatus vir, qui non abiit in consilio impiorum et in via peccatorum non stetit et in conventu derisorum non sedit
Jerome from the Hebrew (JH)	Beatus uir, qui non abiit in consilio impiorum, et in uia peccatorum non stetit, et in cathedra derisorum non sedit.
Septuagint	μακάριος ἀνήρ ὃς οὐκ ἐπορεύθη ἐν βουλῇ ἀσεβῶν καὶ ἐν ὁδῷ ἁμαρτωλῶν οὐκ ἔστη καὶ ἐπὶ καθέδραν λοιμῶν οὐκ ἐκάθισεν

Breaking down the Latin

Secondly, let's look at the Latin with a word by word literal translation:

Beatus (the happy/blessed/fortunate) vir (the man)  qui (who) non (not) abiit (he walked) in consilio (in the council) impiorum (of the wicked) et (and) in via (in the way) peccatorum (of the sinners) non (not) stetit (he stood), et (and) in cathedra (in the seat) pestilentiae (of pestilence)  non (not) sedit (he sat)

The key vocab for the verse is set out below (mainly taken from Britt's Dictionary of the psalter):

beatus, a, um  happy, blessed, fortunate.  Hebrew equiv to ‘O happiness of’

vir, viri, m., a man, any human being,

abeo, ii, itum, ire, to go away, depart;  die; flow;  walk,  to bear, conduct, or deport one's self

consilium, ii, n.   a taking counsel, a deliberation, consultation; His plan, counsel, design.  

impius, ii, m. sinners, the wicked, the godless,

peccator, oris, m.  a sinner, transgressor; the wicked, the godless.

sto, steti, statum, are, to stand, stand up, remain standing. continue.

cathedra, ae. F a chair, seat.

pestilentia, ae, f pestilence, plague 

sedeo, sedi, sessum, ere 2, to sit; dwell, live;  consult with others of a like mind;  to sit on a throne, to rule, reign

The box below provides a number of English translations for comparison purposes.  Note that the Monastic Diurnal and Knox essentially follow the Hebrew Masoretic Text (gathering of scoffers) rather than the Septuagint/Vulgate text tradition.

Douay-Rheims (DR)	Blessed is the man who hath not walked in the counsel of the ungodly, nor stood in the way of sinners, nor sat in the chair of pestilence.
Brenton’s Septuagint (Brenton)	Blessed is the man who has not walked in the counsel of the ungodly, and has not stood in the way of sinners, and has not sat in the seat of evil men.
Monastic Diurnal (MD)	Blessed is the man that followeth not the counsel of the wicked, nor standeth in the path of sinners, nor sitteth in the company of scoffers.
RSV	Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers;
Coverdale	Blessed is the man that hath not walked in the counsel of the ungodly, nor stood in the way of sinners, and hath not sat in the seat of the scornful.
Knox	Blessed is the man who does not guide his steps by ill counsel, or turn aside where sinners walk, or, where scornful souls gather, sit down to rest;

Interpreting the psalm

The first two verses of Psalm 1 can essentially be seen as another way of presenting to us the injunction, 'Turn away from evil and do good'.

True happiness

The psalter opens by asserting that the key reason for turning away from evil is to obtain happiness.

This is counter-intuitive for many: most sins are about self-indulgence and the pursuit of what people falsely perceive as sources of happiness, such as wealth and pleasure.  The Christian view, though, is different.  St Robert Bellarmine, for example, tells us that:

 …happiness, as far at is attainable in this world, is only to be had in conjunction with true justice…”For the kingdom of God is not meat and drink; but justice and peace and joy in the Holy Ghost.”  For the truly just alone are the friends of God...happy is he who is really just...that is to say, who has not followed the counsel, laws, or opinions of the wicked, which are altogether at variance with the way, that is, the Law of God…

Christ as the perfect man who we must imitate

The Fathers (with a few notable exceptions such as SS Hilary and Jerome) generally agree that the blessed man of the psalm should be understood as meaning Christ, since perfect happiness for sinful man is only perfectly attainable in heaven.  St Augustine, for example, explains that: 

This is to be understood of our Lord Jesus Christ, the Lord Man. For He came indeed in the way of sinners, by being born as sinners are; but He "stood" not therein, for that the enticements of the world held Him not. He willed not an earthly kingdom, with pride, which is well taken for "the seat of pestilence;" for that there is hardly any one who is free from the love of rule, and craves not human glory... "the seat of pestilence" may be more appropriately understood of hurtful doctrine; "whose word spreadeth as a canker." For he "went away," when he drew back from God. He "stood," when he took pleasure in sin. He "sat," when, confirmed in his pride, he could not go back, unless set free by Him.

But of course it also applies to those who would imitate him, as Cassiodorus makes clear:

But in Psalm 143 the prophet reminds us that the adjective has two senses: They have called the people blessed that have these things: but blessed is that people whose god is the Lord. So in the worldly sense the blessed man is he who thinks that he is supported by the greatest security, and who continues in abiding joy and worldly abundance. But the psalmist splendidly appended man to the second sense of blessed, which is deterred from its purpose by no opposition. Vir (man) derives from vires, strength.' In his endurance he admits of no failure, and in his prosperity of no proud self-inflation. Rather, he is immovable and steadfast in mind, strengthened by contemplation of heavenly things, and abidingly fearless…

He sees the rest of the verse as excluding Christ from the three faults man is prone to, viz
failings of thought, word, and deed.

The path to perdition

Several of the Fathers and Theologians provide extended explanations of the significance of the walk/stood/sit progression of the verse.

St Thomas Aquinas, for example, points to three stages in the progression of sin in relation to making the choice we all have to make between the path of good and the path of evil: 

As long as a man is deliberating, he is going; second, consent and execution, that is, in operation; He says of the ungodly, because impiety is a sin against God, and of sinners, as against one's neighbour, and in the chair; behold the third, namely to induce others to sin. In a chair thus as an authoritative teacher, and teaching others to sin and therefore he says, pestilence, because a pestilence is an infective disease…Thus there is the right way to happiness, first that we should submit ourselves to God.

St Liguori developed this 'triple gradation of sinfulness' as follows:

• Abiit, one turns away from good - consilio means temptation and impiorum bad principles;
• Stetit, one takes part in evil  - via means going astray, while peccatorum bad conduct; and 
• Sedit, one settles down in it through habit - with cathedra, the giving of scandal, and pestilentia, utter corruption.

Theodoret of Cyrus ties all these ideas together nicely, I think, explaining that the title blessed refers to Christ's divinity, but is one he offers to share with the just:

Very appropriately did mighty David set forth a beatitude as the beginning of his composition, imitating him who is both his son and his Lord – I mean Christ the Saviour – who began his teaching to the holy disciples with the beatitudes: Blessed are the poor in spirit, he said, because theirs is the kingdom of heaven.   

Now, Christ the lord is son of David in his humanity according to that verse of the holy Gospels, Book of the genealogy of Jesus Christ, son of Abraham.  But as God he is his Lord and Creator: his own words are as follows, The Lord said to my Lord, sit on my right.  So he blesses the person who neither shared the way with the ungodly, nor took seriously the counsel of sinners…but shunned the abiding contagion of the corrupt.   

Now the epithet blessed is a divine title; the divine Apostle is witness to this in his exclamation, O blessed and sole rule, King of kings and Lord of lords.  But the Lord God shared this, too, with human beings, as he did other things

Vulgate	Douay Rheims translation
Beátus vir, qui non ábiit in consílio impiórum, et in via peccatórum non stetit, * et in cáthedra pestiléntiæ non sedit	Blessed is the man who has not walked in the counsel of the ungodly, nor stood in the way of sinners, nor sat in the chair of pestilence:
2  Sed in lege Dómini volúntas ejus, * et in lege ejus meditábitur die ac nocte.	But his will is in the law of the Lord, and on his law he shall meditate day and night.
3  Et erit tamquam lignum, quod plantátum est secus decúrsus aquárum, * quod fructum suum dabit in témpore suo:	And he shall be like a tree which is planted near the running waters, which shall bring forth its fruit, in due season.
4  Et fólium ejus non défluet: * et ómnia quæcúmque fáciet, prosperabúntur.	And his leaf shall not fall off: and all whatsoever he shall do shall prosper.
5  Non sic ímpii, non sic: * sed tamquam pulvis, quem prójicit ventus a fácie terræ.	Not so the wicked, not so: but like the dust, which the wind drives from the face of the earth.
6  Ideo non resúrgent ímpii in judício: * neque peccatóres in concílio justórum.	Therefore the wicked shall not rise again in judgment: nor sinners in the council of the just.
7  Quóniam novit Dóminus viam justórum: * et iter impiórum períbit.	For the Lord knows the way of the just: and the way of the wicked shall perish.

You can find the next set of notes in this series here.

Introduction to Psalm 1

The Bamberg Apocalypse, The River of Life, c. 1000

This week I'm going to provide a detailed series on Psalm 1 in the context of the Benedictine Office.

Background on Psalm 1

I have previously provided a more general introduction to it, which you can find here: Introduction to Psalm 1.

I've also provided some short summaries of the psalm by the Fathers, Theologians and a few modern commentators.

Many of the Fathers wrote extended introductions to the psalms in the context of Psalm 1, and easily the greatest of these, in my view, is that by St Basil the Great.  Worth reading also are the comments of St Augustine.  But I have to admit my favourite is not strictly a commentary on it, but a story of its power, viz the conversion story of Fr Mutius from the History of the Monks in Egypt.

Psalm is an introduction to and foundation for the whole of the book of Psalms

Psalm 1 is one of the most important in the psalter.  St Basil the Great for example commented that the foundations and structures around things have to proportionate to their purpose, hence the psalms, so important to the spiritual life, also required a great starting point to inspire us to action:

When architects raise up immensely high structures, they put under them foundations proportionate to the height; and when shipbuilders are constructing a merchantman that carries 10,000 measures, they fix the ship's keel to correspond with the weight of the wares it is capable of carrying. Even in the generation of living animals, since the heart is the first organ formed by nature, it receives a structure from nature proportionate to the animal destined to be brought into existence. 

Therefore, since the body is built around in proportion to its own beginnings, the differences in the sizes of animals are produced. Like the foundation in a house, the keel in a ship, and the heart in the body of an animal, this brief introduction seems to me to possess that same force in regard to the whole structure of the psalms. 

When David intended to propose in the course of his speech to the combatants of true religion many painful tasks involving unmeasured sweats and toils, he showed first the happy end, that in the hope of the blessings reserved for us we might endure without grief the sufferings of this life. 

In the same way, too, the expectation of suitable lodging for them lightens the toil for travelers on a rough and difficult road, and the desire for wares makes mendicants dare the sea, while the promise of the crop steals away the drudgery from the labors of the farmers. Therefore, the common Director of our lives, the great Teacher, the Spirit of truth, wisely and cleverly set forth the rewards, in order that, rising above the present labors, we might press on in spirit to the enjoyment of eternal blessings.

The most abiding image in it though, is that of the second half of the psalm: a tree standing evergreen beside the river.  Most of the Fathers saw this as a reference to the image described in Revelation 22:1-5:

He shewed me, too, a river, whose waters give life; it flows, clear as crystal, from the throne of God, from the throne of the Lamb.  On either side of the river, mid-way along the city street, grows the tree that gives life, bearing its fruit twelvefold, one yield for each month. And the leaves of this tree bring health to all the nations. No longer can there be any profanation in that city; God’s throne (which is the Lamb’s throne) will be there, with his servants to worship him, and to see his face, his name written on their foreheads. There will be no more night, no more need of light from lamp or sun; the Lord God will shed his light on them, and they will reign for ever and ever.

St Jerome, for example, interprets the throne as referring to the Incarnation of Christ; the river as the graces flowing from him through baptism; the banks of the river as the Old and New Testaments, and Christ as the tree, standing on both sides of the river, its wood the wood of the cross.  The fruits of the tree then, are salvation and eternal life, as Theodoret of Cyrus explains:

You see, every practice in life looks toward its goal: athletics looks towards olive wreaths, martial arts towards victories and spoils, medicine certainly towards good health and cure of disease, commerce towards amassing wealth and abundance of riches.  Likewise the practice of virtue has as its fruit and goal the beatitude from God….

Psalm 1 in the Benedictine office

In the light of the importance of this psalm, it is surprising that in the Benedictine Office, Psalm 1 is placed not on Sunday at Matins, at the beginning of the Office each week, as in virtually every other traditional form of the Office, but rather Monday at Prime.  Why is that?

Number symbolism

Part of it, I suspect, is that St Benedict, like many of the Fathers, loved number symbolism.

First, Psalm 1, the Fathers mostly agreed, is above all a description of the Second Person of the Trinity, Christ.  Accordingly, St Benedict places it on the second day of the week (feria II), just as he places the chapter on the abbot, who he explicitly says stands in the place of Christ in the monastery, in chapter two of his Rule.

Secondly, Prime in the Benedictine Office is above all about the triumph of Christ the King (as has long been recognised through the chapter Immortal and eternal king... and versicle  'Arise Christ, and save us' assigned to it), the alpha and omega.

The psalm is labelled one, to he places it at the first hour.  He also gives it 22 psalms each day, the same number as the letters of the Hebrew alphabet, and the first of which each Sunday is a stanza of Psalm 118 in which each line begins with the Hebrew letter aleph.  That all seems to me to suggest the symbolism of Christ first and last (aleph and tau; alpha and omega).

It is worth noting too, that Psalm 1 echoes many of the themes of those stanzas of Psalm 118 said on Sunday (with the other two psalms of Monday picking up most of the remainder).  Indeed, while Psalm 1 starts with the singular 'blessed the man', Psalm 118's plural blessed can be interpreted as the progression that occurs over the symbolic week, from the Incarnation of the single blessed man, Christ, to Christ leading the many into heaven.

The Incarnation

A important reason though may be the association of day II of creation with both the coming of Christ and baptism.  Genesis 1, you will recall, describes the second day of creation as dividing heaven from the earth:

And God said: Let there be a firmament made amidst the waters: and let it divide the waters from the waters. And God made a firmament, and divided the waters that were under the firmament, from those that were above the firmament, and it was so.  And God called the firmament, Heaven; and the evening and morning were the second day.  

The Incarnation is associated with this, because Christ bridges the divide, and draws us after him into heaven through baptism.  St Ambrose's Hexameron, for example, points to the division of the Red Sea (referred to Psalm 113 at Vespers on Monday) as linked to the division of the heavens and the earth on day two of creation.

Certainly, St Benedict's Office is full of both Incarnation and baptismal allusions on Monday, not least in Psalm 1, as St Augustine has pointed out in relation to the verse: and he shall be like a tree planted hard by the running streams of waters:

that is either Very Wisdom, which vouchsafed to assume man's nature for our salvation; that as man He might be the tree planted hard by the running streams of waters; for in this sense can that too be taken which is said in another Psalm, the river of God is full of water. 

The importance of Prime and Psalm 1

In the modern Roman Office, and many Benedictine monasteries today, Prime has been abolished altogether.  And in the new psalm schemas the themes of Psalm 1 are not given much prominence: Psalm 1 itself only appears in the Office of Readings once, to start week one (of four).

In the Benedictine Office, though, the hour includes several very key psalms indeed, including Psalm 1.focuses on several key themes reflected in the Rule, arguably  the essential foundations of how we should live as good Christians.

In the traditional form of the Benedictine Office though, it is one of the four hours with psalms that change for each day of the week.

Prime is very important in the structure of the Benedictine Office!

The text of the psalm

Psalm 1: Monday Prime No 1

Vulgate	Douay Rheims translation
Beátus vir, qui non ábiit in consílio impiórum, et in via peccatórum non stetit, * et in cáthedra pestiléntiæ non sedit	Blessed is the man who has not walked in the counsel of the ungodly, nor stood in the way of sinners, nor sat in the chair of pestilence:
2  Sed in lege Dómini volúntas ejus, * et in lege ejus meditábitur die ac nocte.	But his will is in the law of the Lord, and on his law he shall meditate day and night.
3  Et erit tamquam lignum, quod plantátum est secus decúrsus aquárum, * quod fructum suum dabit in témpore suo:	And he shall be like a tree which is planted near the running waters, which shall bring forth its fruit, in due season.
4  Et fólium ejus non défluet: * et ómnia quæcúmque fáciet, prosperabúntur.	And his leaf shall not fall off: and all whatsoever he shall do shall prosper.
5  Non sic ímpii, non sic: * sed tamquam pulvis, quem prójicit ventus a fácie terræ.	Not so the wicked, not so: but like the dust, which the wind drives from the face of the earth.
6  Ideo non resúrgent ímpii in judício: * neque peccatóres in concílio justórum.	Therefore the wicked shall not rise again in judgment: nor sinners in the council of the just.
7  Quóniam novit Dóminus viam justórum: * et iter impiórum períbit.	For the Lord knows the way of the just: and the way of the wicked shall perish.

 Scriptural and liturgical uses

NT References		Mt 7: 13-14 (v1); Rev 22:2 (v3); Mt 13:40 (v6)
RB cursus		Monday Prime
Monastic feasts etc		(whole psalm): Matins for All Saints,  Easter Sunday, Pentecost,  Corpus Christi,  Common of Martyrs;  Good Friday Tenebrae Easter Sunday Matins AN (v1-2, id 2599) Common of confessor bishop M - AN (v1-3, id 1674) All Saints M AN (v1,6; 3965) Common several martyrs M AN 1.1 v2-3, 4847 [other AN: 4383, 3966,]
Roman pre 1911		Sunday Matins
Matins responsories		3249,7004
Ambrosian		Monday Matins wk 1
Brigittine		Sunday Matins
Maurist		Sunday Matins
Thesauris schemas		A: Sunday Matins wk 1; B: Monday Matins; C: Sunday None; D: Saturday Matins
Roman post 1911		1911-62:Sunday Matins. 1970: Sunday Readings
Byzantine		Kathisma 1 /stasis  1
Mass propers (EF)		Ash Wednesday Communio (vs 2-3)

You can the first set of notes on the verses here

Psalm 20 - Our king will reign forever

Psalm 20: Sunday Matins I, 1 

Vulgate	Douay-Rheims
In finem. Psalmus David.	Unto the end. A psalm for David.
1 Dómine, in virtúte tua lætábitur rex: * et super salutáre tuum exsultábit veheménter.	In your strength, O Lord, the king shall joy; and in your salvation he shall rejoice exceedingly.
2  Desidérium cordis ejus tribuísti ei: * et voluntáte labiórum ejus non fraudásti eum.	3 You have given him his heart's desire: and have not withholden from him the will of his lips.
3  Quóniam prævenísti eum in benedictiónibus dulcédinis: * posuísti in cápite ejus corónam de lápide pretióso.	4 For you have prevented him with blessings of sweetness: you have set on his head a crown of precious stones.
4  Vitam pétiit a te: * et tribuísti ei longitúdinem diérum in sæculum, et in sæculum sæculi.	5 He asked life of you: and you have given him length of days for ever and ever.
5  Magna est glória ejus in salutári tuo: * glóriam et magnum decórem impónes super eum.	6 His glory is great in your salvation: glory and great beauty shall you lay upon him.
6  Quóniam dabis eum in benedictiónem in sæculum sæculi: * lætificábis eum in gáudio cum vultu tuo.	7 For you shall give him to be a blessing for ever and ever: you shall make him joyful in gladness with your countenance.
7  Quóniam rex sperat in Dómino: * et in misericórdia Altíssimi non commovébitur.	8 For the king hopes in the Lord: and through the mercy of the most High he shall not be moved
8  Inveniátur manus tua ómnibus inimícis tuis: * déxtera tua invéniat omnes, qui te odérunt.	9 Let your hand be found by all your enemies: let your right hand find out all them that hate you.
9  Pones eos ut clíbanum ignis in témpore vultus tui: * Dóminus in ira sua conturbábit eos, et devorábit eos ignis.	10 You shall make them as an oven of fire, in the time of your anger: the Lord shall trouble them in his wrath, and fire shall devour them.
10  Fructum eórum de terra perdes: * et semen eórum a fíliis hóminum.	11 Their fruit shall you destroy from the earth: and their seed from among the children of men.
11  Quóniam declinavérunt in te mala: * cogitavérunt consília, quæ non potuérunt stabilíre.	12 For they have intended evils against you: they have devised counsels which they have not been able to establish.
12  Quóniam pones eos dorsum: * in relíquiis tuis præparábis vultum eórum.	13 For you shall make them turn their back: in your remnants you shall prepare their face.
13  Exaltáre, Dómine, in virtúte tua: * cantábimus et psallémus virtútes tuas.	14 Be exalted, O Lord, in your own strength: we will sing and praise your power.

St Benedict's selection of Psalm 20 to open Matins each Sunday was a radical one: starting at Psalm 1 was the norm for all of the traditional forms of the Office, monastic or otherwise.  So why did he do it?

In the Rule, St Benedict explicitly makes a link between this starting point and Prime.  After explaining how the psalms of Prime are to be divided and allocated to each day of the week, he says St Benedict's Rule says:

'Thus it comes about that the Night Office on Sundays will always begin with the twentieth psalm.' (RB18).  

 The Resurrection

The most obvious reason for the linkage is the Resurrection, a fitting opening prayer for the 'Lord's Day' when we celebrate that event afresh each week.

The variable psalmody of Saturday in the Office's mini-Triduum ends with Psalm 19, which, you will recall, is a prediction of the Resurrection and sings the praises of the triumphant king.  Cassiodorus explains its concluding verse, O Lord save the king...' as meaning, 'Let Christ the Lord rise from the dead, ascend into heaven, and intercede for us'.

As St Liguori reminds us, Psalm 20 is a song of the Resurrection:

Hymn of thanksgiving which the people address to God for the victories granted to the arms of David. According to Bellarmine, this psalm is understood in the spiritual sense of the victory which Jesus Christ gained through the merits of his Passion over sin and over hell.

Verse 4 is the key to this interpretation as St Augustine makes clear:

He asked life; and You gave Him: He asked a resurrection, saying, Father, glorify Your Son; and You gave it Him, Length of days for ever and ever. The prolonged ages of this world which the Church was to have, and after them an eternity, world without end.

Life of Christ in a week

The link between Psalm 19 and Psalm 20 also provides a link between that theme and the weekly program around the life of Christ that St Benedict sets out in Matins above all.

St Benedict makes Prime about Christ the King, the first and last, who fulfils the law and leads us into heaven.  But the psalms of that hour also link to the schema that I think is traces out each week the life of Christ from the Incarnation on Monday to the Resurrection on Sunday.

Against the denial of the divinity of Christ

The third reason for St Benedict's approach may have been to make a strong statement against the Arian heresy which was widespread in Italy in his time, and denied the true divinity of Christ.

Cassiodorus saw Psalms 18, 19 and 20 as setting out Christ's two natures, human and divine, and his discussion of Psalm 20 provides a strong exposition of its applicability in countering the Arian heresy (reborn in our time, above all in those who claim Christ was unaware of his divine nature and mission, acted in ways conditioned by the times, and so forth).  He comments:

Here a kind of panegyric is recited about His incarnation, and later the deeds of His divinity are recounted so that all may understand that the Son of Mary ever a virgin is identical with the Word of the Father. Our belief which is conducive to salvation is that there are two natures, divine and human, in Jesus Christ, and they continue in one Person unchangeably for ages without end. This statement should be repeated frequently, because regularly hearing and believing it brings life...

Accordingly, starting with Psalm 20 each week may have been interpreted as a bulwark against that heresy, consistent with the many other anti-Arian features of the Benedictine Office (the addition of the Gloria to each psalm, for example, and the closing 'litany', Kyrie eleison, Christie eleison, Kyrie eleison', which were all adopted in Gaul in the early sixth century specifically to address the heresy).

The eighth day

Above all though, the choice of the psalm surely reflects the eschatological character St Benedict gives Matins.  He sets out his instructions for Matins in the eighth chapter of the Rule; says it should be started at the eighth hour on what was in early Christian parlance the 'eighth day', the dawn of the first day of the new creation ushered in by the Resurrection. And St Athanasius summarises the psalm as revealing:

Christ’s kingdom, and the power of his judgment, and his coming again in the flesh to us and the summoning of the nations.

The Scriptural and liturgical uses of Psalm 20

The psalm arranged for liturgical use:

Psalm 20

Dómine, in virtúte tua lætábitur rex: * et super salutáre tuum exsultábit veheménter.	In your strength, O Lord, the king shall joy; and in your salvation he shall rejoice exceedingly.
Desidérium cordis eius tribuísti ei: * et voluntáte labiórum eius non fraudásti eum.	You have given him his heart's desire: and have not withholden from him the will of his lips.
Quóniam prævenísti eum in benedictiónibus dulcédinis: * posuísti in cápite eius corónam de lápide pretióso.	For you have prevented him with blessings of sweetness: you have set on his head a crown of precious stones.
Vitam pétiit a te: * et tribuísti ei longitúdinem diérum in sæculum, et in sæculum sæculi.	He asked life of you: and you have given him length of days for ever and ever.
Magna est glória eius in salutári tuo: * glóriam et magnum decórem impónes super eum.	His glory is great in your salvation: glory and great beauty shall you lay upon him.
Quóniam dabis eum in benedictiónem in sæculum sæculi: * lætificábis eum in gáudio cum vultu tuo.	For you shall give him to be a blessing for ever and ever: you shall make him joyful in gladness with your countenance.
Quóniam rex sperat in Dómino: * et in misericórdia Altíssimi non commovébitur.	For the king hopes in the Lord: and through the mercy of the most High he shall not be moved
Inveniátur manus tua ómnibus inimícis tuis: * déxtera tua invéniat omnes, qui te odérunt.	Let your hand be found by all your enemies: let your right hand find out all them that hate you.
Pones eos ut clíbanum ignis in témpore vultus tui: † Dóminus in ira sua conturbábit eos, * et devorábit eos ignis.	You shall make them as an oven of fire, in the time of your anger: the Lord shall trouble them in his wrath, and fire shall devour them.
Fructum eórum de terra perdes: * et semen eórum a fíliis hóminum.	Their fruit shall you destroy from the earth: and their seed from among the children of men.
Quóniam declinavérunt in te mala: * cogitavérunt consília, quæ non potuérunt stabilíre.	For they have intended evils against you: they have devised counsels which they have not been able to establish.
Quóniam pones eos dorsum: * in relíquiis tuis præparábis vultum eórum.	For you shall make them turn their back: in your remnants you shall prepare their face.
Exaltáre, Dómine, in virtúte tua: * cantábimus et psallémus virtútes tuas.	Be exalted, O Lord, in your own strength: we will sing and praise your power.

Glória Patri, et Fílio, * et Spirítui Sancto.	Glory be to the Father, and to the Son, and to the Holy Ghost.
Sicut erat in princípio, et nunc, et semper, * et in sǽcula sæculórum. Amen.	As it was in the beginning, is now, and ever shall be, world without end. Amen.

 

NT references	-
RB cursus	Sunday matins
Monastic/(Roman) feasts etc	Ascension; Exaltation of Holy Cross; Common of confessors AN 5478 (4-6); 2963 (6); 1760, 2758, 2759,  (14);
Roman pre 1911	Sunday Matins+AN 2349 (1),
Responsories	7412 (4), 7114 (6), 6682 (14) Ascension no 3, 6681 (14) Common of a martyr: no 6, 6412, v4; no 9, 6341 (3-4); no 11, 6776 (4-6) St Scholastica no 7 (3)
Ambrosian	Tues M wk 1
Brigittine	Monday Sext
Maurist	Sunday M
Thesauris schemas	A: ; B: ; C: ; D:
Roman post 1911	1911-62: Monday Matins. 1970: Vespers (verses 2-8, 14), Tuesday wk 1
Mass propers (EF)	Easter Thurs OF V (cf 3) PP5: AL (2) Vigil of JB, IN (2), CO (5) St Thomas of Canterbury OF (3-6) St Matthew CO (6) Martyr not a bishop IN (2-4), OF (3-6) Martyr bishop TR (3-4)